Method of increasing the strength of textile material



July 26, 1955 L. L. NlcoLAu METHOD OF INCREASINGTHE STRENGTH OF TEXTILE MATERIAL Filed March 18, 1953 INVENTOR. ac clau,

Unite METHD GF INCREASING THE STRENGTH OF TEXTILE Pe/ATERIAL This invention is a continuation-in-part of my cepending application Serial No. 226,444, filed May 15, 1951, now abandoned, and relates to improving strength characteristics of fiber and of fabrics formed therefrom of synthetic or natural, such as animal or vegetable, origin.

More particularly, the invention relates to treatment of fiber or fabrics formed therefrom to increase the strength thereof by developing in situ in the fiber a reaction product of campholide and carnphor with an organic ester of nitric acid, the camphoraceous bodies themselves being developed in situ in the ber from terpenic precursor substances with which the fiber is most readily homogeneously impregnated.

According to the present invention the fiber itself as extruded synthetic staple length fiber, yarn or thread formed therefrom; or as fabric wherein the fiber is matted into fleece, batts or felt or otherwise associated into a fabric such as woven, netted or knitted yarn or thread, have their strength characteristics substantially improved by the treatment hereof. The term textile material as used herein is intended to generically define such tbers or fabrics formed therefrom.

By strength, as the term is used herein, is meant durability and resistance specifically to pressure as bursting strength, tearing strength, or wearing strength in frictional abrasion.

The fibers which may be treated herewith are the natural organic fibers which are swellable in water or liquid organic media, or are fibers of synthetic organic character which are similarly svvellable in water or certain organic liquids and which thereby may be initially impregnated with the specific highly penetrative terpenic substances hereof, pinene hydrochloride, bornyl chloride, an isomer thereof, or both.

Such fibers as wool, silk, cotton, rayon, flax, viscose and other cellulose esters, may be treated by the present method to improve their strength characteristics, either before or after forming into fabrics.

According to the present invention, the fiber is first t treated to imprcgnate the same with pinene hydrohcloride or the hydrochlorination product isomeric therewith, bornyl chloride, preferably dissolved in a solvent in a relatively dilute state, such as 2 to 20%, preferably 3 to 8% solution in a solvent, which may be volatilized at moderate temperatures Without affecting the fiber. Preferably the solvent is one Which tends to swell or impregnate the fiber, somewhat variable with the particular fiber treated. Thus such solvents may be used as Water, monohydroxy lower aliphatic alcohols such as methyl, ethyl, isopropyl, or butyl alcohols, lower' aliphatic ketenes such as acetone, or blends thereof, particularly selected in a manner to have no solvent effect upon the fiber other than swelling.

The terpenic hydrochloride hereof is a hydrochlorination product of a terpene hydrocarbon, usually `a terpentine fraction such as one boiling in the range of 155 to 161 C. rich in alpha pinene. The hydrochlorination of alpha pinene produces pinene hydrochloride, and by low States atent temperature dehydrochlorination and some isomerization during hydrochlorination, will produce bornyl chloride; Either or both of these terpenic hydrochlorides are useful for initial impregnation of the fiber. After impregnation the fiber is dried, usually at slightly raised temperatures such as up to 100 C. to remove the solvent and any water, if prcsent, and leave the fiber homogeneously impregnated with the terpenic hydrochlorination product.

In the second step the impregnated fiber is dehydrochlorinatedby dipping` the fiber or otherwise thoroughly impregnating the, same with an alkaline solution which dehydrochlorinates the terpenic chloride, either pinene hydrochloride or bornyl chloride, to convert the same to camphcne. The reaction is shown by the following equation:

This action is well known, and shown in the literature. See Ullman, page 232, Berichte der deutschen chemischen Gesellschaft, XXlX, page 696 (1896); Berichte der deutschen chemischen Gesellschaft, Lili, page 1815 (1920); Vanino, L., Handbuch der chem. Praparationen, vol'. Il, page 362, Stuttgart (1937); Fisher, H. L., Laboratory Manual of Organic Chemistry, page 259, New York (i938). Any alkali of moderate strength will suffice to effect this dehydrochlorination and for thisY purpose such alkaline substances as caustic soda or potash in dilute aqueous solution, sodium carbonate, sodium phenate, substantially alkaline soaps of alkali metals, or substantially basic organic amines such as aniline or ammonia, may be used.

Treatment of fiber or fabric formed therefrom, particular natural liber such as cotton, wool, silk and the like, with alkalies often tends to harshen the handle thereof and simultaneously stiffen the same. Aklaliue materials having an organic content tend to plasticize the liber, such as sodium phenate, alkaline soaps, organic amines, or aqueous alkaline solutions containing either soap or saponifiable oils, such as animal or Vegetable fixed oils, are preferred; and Where simple inorganic alkaline solutions are used, particularly solutions of strong alkali, such as caustic soda or potash, it is desirable to disperse in the alkaline solution a high molecular organic weight liquid plasticizer which would tend to have a plasticizing or emollient effect upon the liber. Thus, for example, strongly alkaline solutions such as caustic soda or potash or even sodium phenate mayfurther have dispersed therein Vegetable oils in proportion of l to 2% such as coconut oil, peanut oil, palm oil, almond oil, olive oil, or sesame oil, and the like, which may in part. become saponied to a soap containing sufficient excess alkali to neutralize the terpenic hydrochloride and effect dehydrochlorination, or ordinary soap solutions containing an excess of alkali may be similarly used.

The free alkali in solution With the plasticizer is sufficicnt to stoichiometrically react With the hydrogen chloride of the terpenic compound, and is usually applied in from 1/10 to l/ZO molar concentration calculated on the basis of the alkaline ion per se. The dehydrochlorinating treatment of ber with the alkaline solution is preferably effected at raised temperatures, the higher temperature tending to accelerate the rate of reaction and also to initiate a slight polymerization of the camphene formed. Thus some variation in temperature is desirable to adjust the rate of reaction to the travel of the fabric through the treating bath for continuous treatment of the fiber or fabric with respect to other treatments applied in earlier or later stages. For this purpose the temperature of the alkaline solution is desirably maintained in the range of about 75 to 100 C.

Thus, for example, a suitable alkaline bath for treatment of the fabric may be adjusted to contain 75 grams of sodium hydroxide and 190 grams of phenol dissolved in water to the above stated concentration of about 1/30 to 1/20 molar for treating a batch of fiber or fabric containing 100 grams of pinene hydrochloride. To'this solution is further added, homogeneously dispersed therein as a'plasticizer, 1 to 2% of olive oil or other fixed oil, as stated above.

' After thoroughly impregnating the terpenic hydrochloride treated fiber with alkali by dipping in a bath thereof for a period of 2 to 5 minutes, usually about 3, the fiber, now containing camphene homogeneously impregnated therein, is again dried at raised temperatures which may be about 110 C., plus or minus 10 C.

' This dried fiber or fabric in a third step is oxidized with an oxidizing agent, preferably acidic permanganate, dissolved in an organic solvent similar to that of the original impregnating volatile solvent stated above, such I as volatile alcohol or acetone, usually at slightly raised temperatures such as from 30 to 40 C. The oxidation is effected by passing the liber or fabric through an oxidizing bath enclosed to allow recovery of volatilized solvent. This reaction is also known. See Thorpe, Encyclopaedia of Chemical Industry, chapters Camphor and terpenes; or Spanish edition Enciclopedia de Quimica Industrial, page 269, vol. I, Barcelona (1919); Ernst Schmidt, Quimica Farmaceutica, vol. HI, page 370 (Spanish edition: Hijos de l. Espasa, Barkcelona (1911)). It is a direct oxidization with a dilute oxidizing agent and equivalent oxidizing agents known in the art may be substituted. The following reaction takes place:

It will be seen from this reaction that the oxidationV of the camphene produces campholide and camphor in admixture. As used herein, the preferred oxidizing agent is potassium permanganate used in total proportion of about 5 molar equivalents of available oxygen per Ymol of camphene treated. The oxidizing solution is usually used as a dilute aqueous alcoholic solution or acetone solution of about 50 parts each of water and alcohol or 50 parts each of water and acetone containing 3 to 10%, preferfably about 5%, of potassium permanganate. The potassium pcmanganate solution, as conventional in the art for optimum oxidation, is made slightly acidic with sulfuric acid, i. e., in a pH range of about 2 to 6, preferably 2 to 3. The ber or fabric after a 2 to 5 minute oxidation treatment such as by dripping or otherwise impregnating the fiber with solution, preferably about 3 minutes, is next washed with water and again dried at raised temperatures such as about 100 C. However, in the iinal step next described, the treatment is preferably applied to a slightly acidic liber; hence, washing the oxidizing solution out of the iiber is not essential.

In the iinal step the liber or fabric, impregnated in situ as described with camphor and carnpholide, is then treated with an organic nitric ester at normal temperatures. The

nitric ester is a solvent for these terpenes and also reacts Y jected to the alkaline solution for several minutes. the fabric is again dried by a drying device (as shown in with them and thereby effects a more even distribution of the terpenic products in the liber and fixed the same in the iber permanently. After thorough impregnation in a bath of nitric ester at room temperature the ester dissolves and reacts with the terpenes to polymerize and the reaction product is iinally set in the drying thereof, which is applied to the nitric ester wet fabric, the drying being eifected at a temperature of 80 to 100 C.

For this reaction any organic ester of nitric acid having the formula R-NO3, where R is a hydrocarbon radical, desirably liquid, may be used, or where the nitrate is not liquid it may be applied to the fiber as a concentrated solution in any solvent in which it is soluble, in substantial concentration not exceeding that at which it is a free flowing liquid. Various hydrocarbon types of organic radi- .'.tal may be use wherein R is an aromatic radical of the benzene series such as phenyl nitrate, tolyl nitrate, or of the aliphatic series wherein R is methyl, ethyl, propyl, butyl, or amyl nitrate, or mixed aliphatic and aromatic sach as benzyl nitrate. The hydrocarbon radical is preferably selected from those which produce liquid nitrates in which the terpene is soluble, and of this group the sirnple aliphatic nitrates having only a single nitro group such as ethyl, isopropyl or normal butyl nitrate are preicrred. Ethyl nitrate is outstanding of this group as being useful without a solvent, as being suiciently stable to be handled without danger from excessive volatility, and as being highly liquid for thorough impregnation of the fiber and as having a substantial solvent eiiect upon the camphor and campholide for optimum homogeneity of the finally set product in the fiber.

As will be apparent from the description, the fiber is readily treated continuously or in continuous treated batches by passing the same either batch-wise or from a roll of fabric, passing the same in a series from one treatment tank to the next, with intermediate washing and drying operations applied between tanks.

Reference is made to the attached drawing which illustrates diagrammatically a series of tanks useful for treating the fiber according to this invention. For illustrative purposes it is assumed that the fiber is in the form of a fabric but it will be understood that similar apparatus may be used for handling loose iiber batch-wise by mechanically moving the same from tank to tank alternating with drying operations batch-wise. In the drawing, the fabric is unrolled from a bolt or drum A and is passed slowly through the pinene hydrochloride (or bornyl chloride) impregnating tank B wherein the impregnating solution is contained therein as a bath, the fabric being guided therethrough over a series of rollers passing the fabric slowly for thorough impregnation. As the fabric leaves the tank and passes over guide rollers for entry into a second tank it is dried as indicated above, by an intermediate drying chamber not specifically shown at this point to avoid unnecessary duplication, but which may have a construction the same as shown for drying chamber E. It then passes through a tank. C containing an alkaline solution as described above and again out after having been sub- Next , dried (as shown in chamber E) while being carried on intermediate rollers after leaving tank D. Each of said intermediate drying stages may have a drying chamber as shown diagrammatically as tank E, several of which may be mounted between each of tanks B, C and D for drying thereof. The fabric then passes through the final nitric ester tanlf` F wherein it is impregnated with nitric ester such as ethyl nitrate. The fabric is finally heat treated on hot rollers G to finally dry and set the impregnated liber and the dry impregnated cloth is rolled up on roller G. Where the product is to be treated at raised temperature my It. ,ai

the treating tank may have steam coils inthe bottom through which steam is passed at a rate to produce the desired temperature in the liquid. Similarly, steam is passed through the hollow section of the final drying rollers G to heat the same and dry the fabric. Intermediate drying stages are not shown, as indicated, but in each instance a drying chamber such as shown at E or a washing and drying chamber where washing is desired is interposed to effect washing and drying between tanks B, C and D, but no washing is applied to the nitric ester wet fabric.

The fabric treated according to this invention is found to have substantially increased strength and durability. The following examples illustrate the invention:

Example 1.-Cotton dress goods fabric is continuously passed from an unwinding drum A into a first tank B containing a 5% solution of alpha pinene hydrochloride in 95% ethyl alcohol maintained at room temperature, the rate of passage of the fabric being such as to allow it to remain in the bath B as well as in the subsequent treating baths for a period of 3 minutes. It is then dried by passing through a chamber as shown at E maintained at a temperature of approximately 100 C. The dried fabric is then passed into a second tank C containing a solution of sodium phenate in concentration of approximately 115 molar in water, also having suspended therein as an emulsion dispersed in the water 2% of olive oil maintained stable both by the sodium phenate and minor quantities of soap resulting from a partial saponification of the olive oil. The fabric after being treated therewith for 3 minutes at approximately 110 C. at which the alkaline bath is maintained is passed into an intermediate bath (not shown) containing ordinary water for washing the same free of alkali and is again dried in a chamber as shown at E. The fabric is then passed into a tank D and treated therein for 3 minutes at 40 C. with a solution of potassium permanganate dissolved inpequal volume proportions of ethyl alcohol and water maintained in concentration of 5 oxygen equivalents per equivalent of camphene passed therethrough with the fiber, the potassium permanganate being slightly acidied to a pH of 3 with sulfuric acid. The oxidized fabric from tank D is then passed through a washing tank (not shown), is again dried in a chamber E at 100 C. and is finally passed into a tank containing ethyl nitrate (the nitric ester of ethyi alcohol). The ethyl nitrate wet fabric after thorough impregnation with the ethyl nitrate is then passed through hot rollers wherein it is heated and dried on the rollers G at a temperature of 80 to 100 C.

The fabric is found by rubbing tests to have 266% greater resistance to wear than the identical fabric prior to treatment.

Example 2.4-In a series of treatments as set forth in Example 1 applied to diiferent fabrics, the treated fabric was tested in a standard rotary friction meter to test resistance to wear. The following table shows the results listed comparatively:

Percent Ircrease in resistance to Wear Fabric Cotton-viscose tile material with a terpene hydrochloride selected from the group consisting of pinene hydrochloride and bornyl chloride, removing hydrogen chloride from the terpene hydrochloride in situ in said textile material by means of an alkaline solution to convert the same to camphene, oxidizing the camphene impregnated textile material in situ to a mixture of campholide and camphor, reacting the campholide and camphor impregnated textile material in situ with an organic nitric ester having the formula R-NO3, wherein R is hydrocarbon radical, and finally heatinU and drying the textile material thus treated.

2. The method of increasing the strength of textile material comprising homogeneously impregnating the textile material with a terpene hydrochloride selected from the group consisting of pinene hydrochloride and bornyl chloride, removing the hydrogen chloride from the terpene hydrochloride impregnated textile material with a dilute alkaline solution to convert the impregnant to camphene in situ in the textile material, oxidizing the camphene to campholide and camphor, reacting the impregnated textile material with a liquid alkyl nitric ester having the formula R*NO3, wherein R is lower alkyl, and finally heating and drying the textile material thus treated.

3. The method of increasing the strength of textile material comprising homogeneously impregnating the textile material with a terpene hydrochloride selected from the group consisting of pinene hydrochloride and bornyl chloride, removing the hydrogen chloride from the terpene hydrochloride in situ in said textile material by means of a dilute alkaline solution to convert the same to camphene in situ in the textile material, oxidizing the camphene in situ to campholide and camphor, reacting the impregnated textile material in situ with ethyl nitrate having the formula CzHs-NOs, and finally heating and drying the textile material thus treated.

4. The method of increasing the strength of textile material comprising homogeneously impregnating the textile material with pinene hydrochloride, removing the hydrogen chloride from the terpene hydrochloride impregnated textile material with a dilute alkaline solution to convert the impregnant to camphene in situ in the textile material, oxidizing the camphene in situ to campholide and camphor, reacting the impregnated textile material with ethyl nitrate having the formula C2H5-NO3, and finally heating and drying the textile material thus treated.

5. The method of increasing the strength of textile material comprising homogeneously impregnating the textile material with bornyl chloride, removing the hydrogen chloride from the bornyl chloride impregnated textile material with a dilute alkaline solution to convert the impregnant to camphene in situ in the textile material, oxidizing the camphene in situ to campholide and camphor, reacting the impregnated textile material with ethyl nitrate having the formula C2H5-NO3, and finally heating and drying the textile material thus treated.

6. The method of increasing the strength of textile material comprising homogeneously impregnating the textile material with a terpene hydrochloride selected from the group consisting of pinene hydrochloride and bornyl chloride, removing the hydrogen chloride from said terpenic chloride with a dilute alkaline solution containing a plasticizer for the textile material to convert the hydrochloride in situ to camphene, oxidizing the camphene in situ with a dilute solution of an oxidizing agent to convert the camphene to a mixture of campholide and camphor, reacting the camphor impregnated textile material with ethyl nitrate having the formula C2H5-NO3, and finally heating and drying the textile material thus treated.

References Cited in the le of this patent Whitemore: Organic Chemistry, 1946, pp. 667, 668, 672, 673, 676.

Karrer: Organic Chemistry, fourth English edition, 1950, pp. 688, 699, 702. 

1. THE METHOD OF INCREASING THE STRENGTH OF TEXTILE MATERIAL COMPRISING HOMOGENEOUSLY IMPREGNATING THE TEXTILE MATERIAL WITH A TERPENE HYDROCHLORIDE SELECTED FROM THE GROUP CONSISTING OF PINENE HYDROCHLORIDE AND BORNYL CHLORIDE, REMOVING HYDROGEN CHLORIDE FROM THE TERPENE HYDROCHLORIDE IN SITU IN SAID TEXTILE MATERIAL BY MEANS OF AN ALKALINE SOLUTION TO CONVERT THE SAME TO CAMPHENE, OXIDIZING THE CAMPHENE IMPREGNATED TEXTILE MATERIAL IN SITU TO A MIXTURE OF CAMPHOLIDE AND CAMPHOR, REACTING THE CAMPHOLIDE AND CAMPHOR IMPREGNATED TEXTILE MATERIAL IN SITU WITH AN ORGANIC NITRIC ESTER HAVING THE FORMULA R-NO3, WHEREIN R IS HYDROCARBON RADICAL, AND FINALLY HEATING AND DRYING THE TEXTILE MATERIAL THUS TREATED. 